Field of the Invention:
The present invention relates to methods and apparatuses that help patients adhere to an injection site rotation plan to minimize lipodystrophy and related adverse effects such as reduced or erratic medicament absorption and associated difficulties with managing a health condition employing the medicament as part of a care plan.
Description of Related Art:
Patients requiring frequent skin invasive actions such as injections or infusions of medicament into the skin can develop lipodystrophy at the injection sites. Lipodystrophy is a degenerative disorder of subcutaneous tissue. One type of lipodystrophy is lipohypertrophy, which can present in a patient as thickening of tissue such as lumps, or dents, or red and swollen tissue that is hard when palpated, in the affected area. The term “injection” as used herein can be, for example, injection by a needle (e.g., single dose syringe, or injection pen), or by infusion (e.g., a medicament pump with cannula for subcutaneous insertion such as an insulin pump), or any other action by which a patient's outer skin is pierced or crossed to deliver a medicament or to take a sample (e.g., a blood or tissue sample).
Lipodystrophy can be problematic for the patient because it can affect the rate of absorption of the medicament being administered by injection. For example, insulin therapy relies on reproducible absorption of insulin from a patient's subcutaneous (SC) tissue. Some patients with diabetes may require injections of a medicament (e.g., insulin) several times per day. Repeated application of insulin in a small skin area of a patient can induce lipodystrophic changes in the patient's skin structure (e.g., in the fatty tissue in the SC space). For example, a patient can suffer from lipodystrophy in an affected body area when he injects in that same body area and too close to adjacent injection sites in that area within a time period that is too short in duration to allow these injection site(s) to recover from the skin invasive action of the injection(s). Injection of insulin into a body area affected by lipodystrophic changes to the skin structure (e.g., SC tissue that may be fibrous and relatively avascular) can, in turn, induce erratic insulin absorption since a lack of blood vessels in the vicinity of the injection location (i.e., insulin depot) can reduce the rate of insulin absorption. For diabetic patients who administer insulin by injection or infusion techniques, less than optimal rate absorption can cause increased insulin requirements and/or poor metabolic control. Alternatively, a faster absorption rate may occur, which leads to poor glucose control.
Illustrative injection regimens will now be described with respect to insulin administration to diabetic patients. It is to be understood that the illustrative embodiments of the invention described below are applicable to other types of medical conditions requiring repetitive injections, and to other types of injection regimens using other types of medicament. Example injection regimens are:
Conventional therapy: use fast-acting and intermediate-acting types of insulin, typically requiring 2-3 injections per day;
Multiple daily injections (MDI): mealtime injections of fast-acting insulin to manage blood sugars during a meal and in the post-prandial period, and an injection of long-acting insulin manage blood glucose levels between meals, which can be at least 4 injections per day; and
Continuous subcutaneous insulin infusion (CSII): administer insulin through a temporary flexible catheter inserted into subcutaneous tissue and worn in rotating sites for 2-3 days or 4-5 days. Lipohypertrophy can occur in body areas used for continuous insulin delivery systems (e.g., subcutaneous indwelling catheters and insulin pump), as well as injections using syringes or pen needles. Although patients may be instructed to avoid placing catheters in areas of lipohypertrophy, these areas are not necessarily recognized by patients or their caregivers and, as such, catheters are often placed where early lipohypertrophy is already present.
Evidence suggests a correlation between lipodystrophy, and failure to rotate injection sites or using small injection zones (e.g., body areas) repeatedly or injecting into the same location and/or re-using needles. Systematic site rotation can help to reduce the risk of developing lipohypertrophy. Thus, an easy-to-follow injection site rotation plan or scheme taught from the start of injection therapy is recommended.
With reference to FIG. 23A, eight body areas have been identified for insulin administration, that is, right and left sides of the patient's abdomen, arms, buttocks, and thighs. An important part of a care plan for a diabetic patient is education on and implementation of an injection site rotation plan. A site rotation plan can include injections or catheterization with an infusion device in a single body area (e.g., the abdomen) but using a pattern or grid to help distribute injections over this area. For example, one illustrative rotation scheme divides the area surrounding a patient's umbilicus (e.g., a target body area for injections), into sections (e.g., body area zones) such as the 12 hours of a clock face as shown in FIG. 24, or quadrants centered with respect to the umbilicus or halves of a body area such as the thigh as shown in FIG. 23B, to help a patient distribute injection sites within that body area.
The injection site rotation plan can also involve plural body areas. For example, other illustrative rotation schemes can include, but are not limited to, a patient rotating shots among plural body areas in a given day, or distributing shots within the same selected body area for a selected time period (e.g., a week) before rotating to another body area to distribute shots therein for the selected time period. One scheme with proven effectiveness involves dividing the target body area for injection sites into quadrants or halves, depending on the size of the area, using one quadrant or half per week, rotating within that area from day to day, and then moving clockwise each week to a new area1. 1 Pledger et al. “Importance of Injection Technique in diabetes” Journal of Diabetes Nursing 16 No 4 2012 pp 160-165.
Many patients, however, do not adhere to an adequate injection site rotation plan to avoid or minimize lipodystrophy and its related problems. For example, even when advised to rotate injection sites, patients continue with a less than optimal routine of using too few body areas and injection sites for different reasons. One reason is the Human Factor or ergonomic ease with which a patient can reach his or her different body areas to self-inject. For example, a patient's abdomen and thighs may be easier to reach with her hands to self-inject than her back or arms. As stated above, lipodystrophy can occur because a patient injects the same site day after day. It frequently occurs on both sides of the umbilicus or in the mid-thigh areas as these are convenient places to inject for diabetic patients. Another reason patients may purposefully or even unconsciously fail to practice an adequate injection site rotation plan is fear of pain in new sites. Further, some patients simply adhere to a less than optimal injection site rotation plan out of habit and for no particular reason other than not having adequate reminders or encouragement to rotate injection sites before lipodystrophy occurs. A need therefore exists for methods and/or apparatuses that encourage a patient to adhere to an injection site rotation plan such as, but not limited to, provide reminders, or help the patient keep record of past injection sites and select the next target body area and/or injection site.
In addition, rotation schemes may not sufficiently distribute injections over a target body area. For example, one rotation plan may provide 2 or 4 target areas (e.g., left, right thigh and/or left, right abdominal area), but leave where in that area to inject to the discretion of the patient, resulting in the patient most likely locating injections in only a few concentrated locations or injection sites within the target body area. A need therefore also exists for methods and/or apparatuses that help a patient distribute injection sites within a target body area.
Effective injection site rotation is therefore an important component to medicament administration. Early detection of a lipodystrophic site or site at imminent risk for developing lipodystrophic characteristics, and refraining from using such a site for a selected period of time, may preserve that site for future medicament delivery. Some sites need to be avoided for a period of time or avoided altogether, depending on the degree of damage done to the tissue. Further, injection sites need to be not only visually examined but also palpated since not all skin lesions are visible. A need therefore exists for methods and/or apparatuses that help a patient track lipodystrophic sites and avoid using them as target injection sites for at least a selected period of time, and optionally to help a patient discern whether a particular site on his or her body is developing lipodystrophic characteristics.
A variety of devices for administering insulin are available to diabetic patients, and range from unit dose disposable syringes, to reusable pen injectors, to infusion sets. A need therefore also exists for methods and/or apparatuses that encourage patients to adhere to an injection site rotation plan as well as accommodate their choice of insulin delivery mechanism.